clk: u300: Remove clk.h include

Clock provider drivers generally shouldn't include clk.h because
it's the consumer API. Remove the include here because this is a
provider driver. Also add in slab.h because without clkdev.h
compilation of this file would fail.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk-u300.c

@@ -5,8 +5,8 @@
  * Author: Linus Walleij <linus.walleij@stericsson.com>
  * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
  */
-#include <linux/clk.h>
 #include <linux/clkdev.h>
+#include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/clk-provider.h>